Remove unnecessary `explicit` qualifiers on constructors.

Change-Id: Id12e392ad50f66a6e2251a68662b7959315dc567
diff --git a/compiler/utils/dedupe_set.h b/compiler/utils/dedupe_set.h
index 8cdb180..2c4a689 100644
--- a/compiler/utils/dedupe_set.h
+++ b/compiler/utils/dedupe_set.h
@@ -99,7 +99,7 @@
     return hashed_key.store_ptr;
   }
 
-  explicit DedupeSet(const char* set_name, SwapAllocator<void>& alloc)
+  DedupeSet(const char* set_name, SwapAllocator<void>& alloc)
       : allocator_(alloc), hash_time_(0) {
     for (HashType i = 0; i < kShard; ++i) {
       std::ostringstream oss;